基于DEM的商洛市水土流失分析

目的：运用ArcGIS软件对商洛市地形因子进行分析,探讨其对水土流失的影响。方法：以商洛市为研究区域,采用数字高程模型（Digital Elevation Model,DEM）数据,选取坡度、坡长、沟壑密度及地表切割深度4个指标对水土流失程度进行分析。结果：商洛市急陡坡主要集中在西南部的镇安县及周边,缓倾斜坡主要集中于商洛市北部的洛南县及周边区域;商洛市中部的商州区、丹凤县、柞水县东部及山阳县东北部等地区坡长均在35 m以上,其它区域坡长较短;商洛市西南部大部分区域的地表切割深度在200 m以上,其它区域地表切割深度较小;商洛市沟壑密度均值1.20 km/km2,密度较小。结论：商洛市中部及西南山区水土流失较重,坡度、坡长及地表切割深度3个地形因子对商洛市水土流失的影响显著     

基于不同因子分级的滑坡易发性区划对比——以万州区为例

[目的]基于滑坡点属性与研究区全域点属性作为分类基础数据,对位于三峡库区的万州区滑坡易发性区划对比研究.[方法]选取高程、多年平均降雨量、地表切割深度、坡向、距道路距离、坡度、POI核密度、倾坡类型、岩性、归一化植被指数、曲率、地形起伏度、地形湿度指数等13个因子作为影响因子,分别对滑坡点属性与研究区全域点属性使用 自然断点法进行因子分类,并通过两种分类结果构建模型预测研究区内滑坡易发程度的空间分布情况.[结果]以研究区全域点属性作为分类数据对应的曲线下面积(Area under curve,AUC)值为0.79,对应的模型测试集最高精度为0.755;以滑坡点属性作为分类数据对应的AUC值为0.85,对应的模型测试集最高精度为0.779;高程、地表切割深度和多年平均降雨量的重要性位于前3位,对滑坡的发生有较大影响.[结论]采用滑坡点属性确定因子分类标准建立的随机森林模型精确性和预测能力更优,可对万州区的滑坡灾害危险管理和影响因子分级研究提供参考.     

基于DEM和均值变点法的伏牛山区地形起伏度分析

以100 m分辨率的DEM为基础数据,在GIS技术和SPSS软件的支持下,采用邻域分析法,分别在29个大小不同的矩形分析窗口下提取伏牛山区地形起伏度,采用均值变点法计算出地形起伏度的最佳统计单元,最后绘制伏牛山区地形起伏度的分级图,并进行空间差异特征分析.结果表明:(1)运用均值变点法得到伏牛山区地形起伏度的最佳统计单元为11×11像元的分析窗口,对应的窗口面积为1.21 km~2.(2)基于计算出的最佳统计单元提取伏牛山区地形起伏度,并划分为5个等级.整体来看,伏牛山区以地形起伏度为200～500 m的中起伏为主,占53.27%,主要位于中高山地区;其次是地形起伏度为70～200 m的小起伏地形,占26.14%,主要分布在中低山地区;微起伏(30～70 m)和平坦(0～30 m)地区占18.85%,主要位于东南部和东部山麓地带;大起伏地区所占比例最小,仅为1.74%,主要分布在山脉主脊地带.(3)地形起伏度与坡度的拟合度高于与海拔的拟合度,且随海拔高度和坡度增加,其高值区所占比重分别呈逐渐增加趋势,表现出较强的海拔与坡度规律性.     

山城土地定级地形因素评价方法探讨——以重庆市主城区为例

在山地城市中，地形对土地质量有土地利用方式产生着深刻的影响，受地形地貌影响，重庆市城市发展在垂直方向和水平方向表面出不同的特点，从分析地形的主要因素地面坡度、地面起伏度和切割密度入手，提出在山地城市土地定级中可采用地貌网格法划分地貌单元，定量地计算地貌单元分值的方法。     

复杂地形下最小起伏度直线选址研究

地形的起伏度是反映地形起伏的宏观地形因子,是描述区域地形地貌变化的地形指标,在区域性研究中,应用DEM数据提取地形起伏度能够快速、直观地反映地形的起伏特征。利用地形起伏度来进行最小起伏度的直线路径选址具有重要的理论和实践意义。本文以四川丹巴地区的DEM数据和TM数据为实验数据,应用Hough变换和从DEM提取地形起伏度的基本算法,通过对比分析,确定该地区起伏度最小的地形剖面。通过对实验结果的对比分析证明,该方法是一种有效的方法。     

数字地形特征对土地利用空间分布的定量影响

 为了获取地形对土地利用空间分布的定量影响,以山西省为研究区,基于数字高程模型（DEM）数据生成4种地形因子（海拔高度、起伏度、坡度和坡向）表征数字地形特征,并通过遥感影像解译获得土地利用空间分布,利用地理探测器方法定量分析地形因子对土地利用空间分布的分异性、相关性及其交互作用的定量影响。研究结果表明：起伏度与坡度的空间分异性最显著（显著性水平p<0.01）;起伏度空间相关性最强（空间统计量q=0.012）,其次为坡度（q=0.010）;任意两种地形因子交互均具有非线性增强作用,其中海拔高度与起伏度的交互作用最强（q=0.034）。因此,起伏度是影响土地利用空间分布最重要的单个地形因子,它和海拔高度一起对土地利用空间分布发挥重要作用。     

土地利用影响因素的微观分析——以关中地区为例

以遥感解译获取的土地利用数据为变量,自然和社会经济数据为自变量,采用多源数据融合的方法,基于空间自回归模型对关中地区3种主要土地类型的影响因素进行了微观分析.结果表明:与林地分布相关的主要因素为坡度和地形起伏度,与耕地分布相关的主要因素为坡度、地形起伏度和有机质含量,与建设用地相关的主要因素为地形起伏度、河网密度和道路通达度;通过模型的比较研究,考虑空间自相关因素的空间自回归模型能较好地从空间上解释土地利用格局的影响因素.     

天津地区闪电活动与地形因子关系研究

为研究天津地区闪电活动与地形因子的关系,文章采用相关分析、多元线性回归方法,对天津地区2008—2013年闪电定位数据和30m精度的DEM数据(提取海拔、坡向、坡度、坡度变率、地形起伏度)进行分析,结果发现闪电频数与海拔、坡度变率、地形起伏度呈负相关关系,与坡度呈正相关关系,与坡向不相关,闪电电流强度与坡度呈正相关关系,与其他地形因子不相关。     

地理信息系统在地质灾害评估中的应用分析

本文在对地理信息系统（GIS）和地质灾害评估简要说明的基础上,归纳总结了GIS应用于地质灾害评估的研究方法,最后结合具体案例对GIS在地质灾害评估过程中的应用进行分析。结果表明基于GIS的地理模型分析方法,实现了地形起伏度、坡度、坡向等地理因素对评估地理区域地形地貌特征的定量描述,可以为地质灾害的评估提供所需的动态地理空间信息和地形分析数据,从而为地质灾害的评估和决策部门提供科学依据。     

基于ArcGIS的坡面复杂度因子提取与分析——以黄土高原为例

通过黄土高原坡面复杂度因子提取与分析,得到其地貌分区图,为黄土高原的土地利用与评价、地质地貌研究提供参考和借鉴.采用黄土高原地区90 m分辨率的SRTM Elevation Data的DEM数据,利用ArcGIS软件提取了坡面复杂度因子,包括地形起伏度、地表切割深度、地表粗糙度和高程变异系数,并对这些因子进行逐个分析.在此基础上得到黄土高原的地貌分区图.研究表明,黄土高原地区总的地势是西北高、东南低,区内宏观地貌类型复杂多样,山区、丘陵区、高原区占2/3以上;东南部是黄土丘陵沟壑区和黄土高原沟壑区,西北部为风沙、干旱草原和高地草原区,中部三大高原地表破碎、沟壑纵横,北部银川平原、河套平原和南部渭河平原地形相对平缓.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.